1. Field
Apparatuses and methods consistent with exemplary embodiments relate to capturing an image of an object through automatic determination of a focal region.
2. Description of the Related Art
In general, a focus method may be classified into contrast auto focus and phase auto focus.
FIG. 1A is a diagram explaining contrast auto focus. The contrast auto focus is to adjust a lens position up to a position having the highest contrast using the characteristic that an accurately focused photo has a clear contour to heighten the contrast whereas an unfocused photo has an unclear contour to lower the contrast. That is, according to the contrast auto focus, focusing is performed by measuring the contrast for each lens position as changing the lens position and adjusting the lens to the lens position having the highest contrast.
FIG. 1B is a diagram explaining phase auto focus. The phase auto focus is to detect an actual focus position after determining to what extent an object is focused using a phase difference between phase-sensed pixels in an image.
A small camera uses the contrast auto focus which has drawback of low speed while a digital single-lens reflex (DSLR) camera uses the phase auto focus which has drawback of inaccuracy in comparison to the contrast auto focus. Accordingly, a method for obtaining a focus through mixing of the two methods as described above has recently been developed.
However, even in the case of using the method for obtaining a focus through mixing of the two methods, the DSLR camera provides a plurality of focal regions as illustrated in FIG. 2A, and thus a desired object is unable to be focused unless a user determines any one of the plurality of focal regions. That is, it is required to determine the focal region regardless of the focusing method.
In a small camera, a function of determining the focal region through recognition of a human face as shown in FIG. 2B may be provided. However, if the object is not the human face, the use of such a function is restricted.
Further, if the contrast auto focus is used to adjust the focus in a small camera, contrast values as shown in FIG. 1A may be obtained. In this case, the small camera determines the lens position that corresponds to the highest contrast value on the right side. However, a user may desire to set the lens position that corresponds to the second highest contrast value on the left side. In this case, additional use of the phase auto focus is unable to solve such a problem, and the user is unable to capture an image of a desired object.